A. Subject Matter
This invention relates to apparatus for imparting an undulatory configuration to a strand of wire.
B. Prior Art
This invention comprises an improvement over known apparatus for imparting an undulatory configuration to a strand of wire. Prior to this invention, and to the invention over which this is an improvement, machines were known for imparting an undulatory configuration to a strand of wire which conventionally utilized a pair of serrated complimentary dyes for engaging the wire and bending it into the desired configuration. Such devices are necessarily reciprocal in nature and hence are characterized by high inertia and inherent low operating speed. Such known dye devices are not only expensive to build but require a substantial maintenance effort if a satisfactory product is to be formed.
In this respect major efforts have been directed to the development of apparatus and methods for imparting an undulatory configuration to a strand of wire wherein reciprocal parts are eliminated and rotatable elements are used instead. In an initial effort to accomplish such a desired result a pair of wheels were disposed along side each other and rotatably mounted on axes which were angularly disposed so that a plurality of pins disposed about the peripheries of both wheels were caused to occupy spaced relationships which continuously varied throughout each revolution of the wheel. This space variation allowed rapid formation of loops of wire about the pins followed by a tightening of the loops due to increased spacing between the particular pin on one wheel and the adjacent pin on the other wheel. Thus a permanent set was imparted to the wire according to this particular feature of the invention which involved the angular displacement of the rotating wheels. Various mechanisms for securing the wire in place on the rotating wheels and for removing the wire are provided in accordance with specific features of the apparatus of the prior art. See in particular U.S. Pat. No. 3,691,808 issued Sept. 19, 1972 to Calvert et al.
While the above recited Calvert et al. patent does disclose the use of angularly disposed rotatable wheels having a plurality of pins secured to the periphery of each of said rotatable wheels to impart an undulatory configuration to a strand of wire a disadvantage of the apparatus of Calvert et al. is in what is referred to hereinafter as the wire looping assembly. The wire looping assembly of the Calvert et al. patent comprises a rotatable device having lateral projecting arms thereon engaging the wire as the wire is fed into the wire looping assembly and subsequently loops the wire about a pair of pins disposed respectively on the peripheries of a pair of rotatable wheels. This wire looping assembly and specifically the rotatable element with the arms disposed thereon has led to serious commercial difficulties in terms of maximum operating speed and downtime for repairs. In addition this rotatable element comprising the primary element of the wire looping assembly is difficult to mechanically actuate as it requires a discontinuous action which is not easily converted from standard drive means. In addition the wire forming apparatus of the Calvert et al. patent requires releasing means to operate by an oscillating motion to periodically displace the strand of wire from contact with the rotating element. All of these elements which comprise the commercial limiting elements of the entire wire forming apparatus have been eliminated and/or improved by applicants' invention.